When he played Lenny on ABC's popular 1976-83 sitcom "Laverne & Shirley," Michael McKean realized he could easily become typecast as his dumb, lovable Fonzie wannabe and pal of the knuckleheaded Squiggy. He vowed not to let it happen.

"It's not your first gig that typecasts you, it's the next two," said the affable McKean, 65, during a recent lunch break from rehearsals of his latest gig as British Prime Minister Jim Hacker in the British political comedy "Yes, Prime Minister," which begins previews Tuesday and opens June 12 at the Geffen Playhouse.

"If the next two are just like the first one, you're typecast. You have shot yourself in the foot. When I was doing 'Laverne & Shirley,' ABC said, 'You have to be on 'The Love Boat.' It was exactly the same character. I said, 'I don't want to play another idiot.'"

So he waited. Patiently. Then he did Garry Marshall's 1982 comedy "Young Doctors in Love." Audiences and critics were shocked that the goofball Lenny was not only handsome but deft at playing romantic comedy.

And McKean has never looked back — or played the same role twice.

In fact, he's become a man of a thousand comedic faces. Especially in his collaborations with Christopher Guest ,whether it be as David St. Hubbins, the singer-guitarist of a hapless heavy metal group in Rob Reiner's 1984 mockumentary, "This Is Spinal Tap," or as Stefan Vanderhoof, a gay man with a prize-winning Shih Tzu in Guest's 2000 "Best in Show" or as Keith Chadwick, the distracted father of a clueless 30-year-old (Chris O'Dowd) who spends most of his days watching old sitcoms in Guest's first TV series, "Family Tree," on HBO.

A talented musician and songwriter, McKean, along with actress wife Annette O'Toole, also earned a best song Oscar nomination for "A Kiss at the End of the Rainbow" from Guest's 2003 comedy "A Mighty Wind."

"Yes, Prime Minister" director and co-writer Jonathan Lynn ("My Cousin Vinny") had worked with McKean in the 1985 comedy film "Clue."

"I watched him over the years and went to New York and saw him in Gore Vidal's 'The Best Man.' He was awfully good in it," Lynn recalled. "It occurred to me he might be a really good Jim Hacker. I expected him to bring a great deal to the role, and that's what he's doing."

Lynn and Antony Jay introduced the character Hacker in the 1980s in their popular British comedy series "Yes, Prime Minister." Lynn and Jay's theatrical version, in its third tour of England, spawned a new TV series.

The political satire finds Hacker returning to duty as prime minister after several years out of office and enduring the worst day in his life.

"I think my intentions are good," said McKean of Hacker. "Occasionally, it slips through that I am not a great man, but I am not exactly mediocre because during the course of the play I find ways to work the system."

The day of the interview happened to mark the one-year anniversary of the actor's breaking his leg and suffering facial lacerations when a car jumped a curb and plowed into him at 86th Street and Broadway in New York. "I was in the hospital for about 21/2 weeks and then had a lot of physical therapy," he said.

Less than six months after the accident, McKean began work in London on "Family Tree."

O'Dowd ("Bridesmaids," "Girls") was struck by McKean's "genuine warmth" when they first met, "Some actors can be kind of standoffish and aloof when you first meet them. He couldn't have been more different that that. He was like 'Welcome to the group and let's go and do something great.'"

Ironically, it was music, not comedy, that brought together McKean and Guest when they were students at New York University.

"We were both into rock 'n' roll and music," said McKean. "He was a guitarist, and I was a guitarist. We actually had the same electric Gibson. We were roommates for a while. That's when we started writing songs."

Four years ago, McKean, Guest and Harry Shearer went out on an "Unwigged and Unplugged" tour in which they performed, sans costumes, songs from "Spinal Tap" and "A Mighty Wind."

"We did two costume gigs in [Britain]," said McKean. "We played Wembley Arena. We did Glastonbury. It was pretty nice. There were 45,000 to 50,000 people."